docs: def save(self) -> None:
          """
          Saves the contents of the source manager to disk.
          """
          logger.info('saving registry to: %s', self.__registry_fn)
          d = [s.to_dict() for s in self]
  
          os.makedirs(self.__path, exist_ok=True)
          with open(self.__registry_fn, 'w') as f:
              yaml.dump(d, f, indent=2, default_flow_style=False)
          logger.info('saved registry to: %s', self.__registry_fn)